begin

begin is a skill for Claude Code, Codex from SienkLogic/plan-build-run. It costs 17 tokens per session (10,586 once invoked), scanned A, original, MIT.

A guided workflow for starting a new software project through questions, research, requirements, and a roadmap.

In plain words
What is it for?
It helps gather requirements, research options, define project boundaries, and create an initial development plan.
Why use it?
It turns an early idea into a clearer scope and sequence of work before implementation begins.

Skill for Claude CodeCodex

Installs and runs on its own, but its text points at files inside its plugin — anything it tells you to read at a ${CLAUDE_PLUGIN_ROOT} path is only there once the plugin is installed. Installing the plugin gets both.

Part of the pbr plugin — 45 skills, 71 commands, 18 agents, 3 hooks shipped together

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/sienklogic/plan-build-run/begin
Any agent
npx skills add SienkLogic/plan-build-run --skill begin
Clone the repo
git clone --depth 1 https://github.com/SienkLogic/plan-build-run

Made for: Claude Code, Codex.

Or install pbr, the plugin that ships this one along with the rest of its 45 skills, 71 commands, 18 agents, 3 hooks.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for begin

README.md
[![agentmods](https://agentmods.dev/badge/skills/sienklogic/plan-build-run/begin.svg)](https://agentmods.dev/skills/sienklogic/plan-build-run/begin)
Your own site
<a href="https://agentmods.dev/skills/sienklogic/plan-build-run/begin"><img src="https://agentmods.dev/badge/skills/sienklogic/plan-build-run/begin.svg" alt="Measured on agentmods" height="20"></a>
Per session 17 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 10,586 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00017 $0.10586
Opus 5 $0.00009 $0.05293
Sonnet 5 $0.00003 $0.02117
Haiku 4.5 $0.00002 $0.01059

Measured yesterday against content hash 84bd8c463068, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

begin scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/pbr/skills/begin/SKILL.md · 977 lines

How it starts

The opening of the file, as written. The whole thing — 977 lines — stays where its author put it; the contents beside it link to each section on GitHub.

STOP — DO NOT READ THIS FILE. You are already reading it. This prompt was injected into your context by Claude Code's plugin system. Using the Read tool on this SKILL.md file wastes ~7,600 tokens. Begin executing Step 1 immediately.

/pbr:new-project — Project Initialization

References: @references/questioning.md, @references/ui-brand.md

You are the orchestrator for /pbr:new-project. This skill initializes a new Plan-Build-Run project through deep questioning, optional research, requirements scoping, and roadmap generation. Your job is to stay lean — delegate heavy work to Task() subagents and keep the user's main context window clean.

Context Budget

Reference: skills/shared/context-budget.md for the universal orchestrator rules. Reference: skills/shared/agent-type-resolution.md for agent type fallback when spawning Task() subagents.

Additionally for this skill:

  • Minimize reading subagent output — read only summaries, not full research docs
  • Delegate all analysis work to subagents — the orchestrator routes, it doesn't analyze

Step 0 — Immediate Output

Before ANY tool calls, display this banner:

╔══════════════════════════════════════════════════════════════╗
║  PLAN-BUILD-RUN ► STARTING PROJECT                           ║
╚══════════════════════════════════════════════════════════════╝

Then proceed to Step 1.

Multi-Session Sync

Before any phase-modifying operations, this skill acquires a claim on the project:

acquireClaim(planningDir, sessionId)

Where planningDir is the .planning/ directory and sessionId is the current session identifier. If the claim fails (another session owns it), display: "Another session owns this project. Use /pbr:progress to see active claims."

On completion or error, release the claim:

releaseClaim(planningDir, sessionId)

Prerequisites

  • Working directory should be the project root
  • No existing .planning/ directory (or user confirms overwrite)

Read the full file on GitHub · 977 lines

Files

What ships with it

7 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 977 lines · 17 tokens per session scan A 84bd8c463068

Subscribe to this mod's changes

begin is a skill published in the GitHub repository SienkLogic/plan-build-run (17 stars, last pushed 5mo ago), licensed MIT. It adds 17 tokens to every session and 10,586 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

Related

Other skills, from other repositories

repo-recap

Generate a comprehensive repo recap (PRs, issues, releases) for sharing with team. Pass "en" or "fr" as argument for language (default fr).

rtk-ai/rtk · 34 tokens

rtk-triage

Triage complet RTK : exécute issue-triage + pr-triage en parallèle, puis croise les données pour détecter doubles couvertures, trous sécurité, P0 sans PR, et conflits internes. Sauvegarde dans claudedocs/RTK-YYYY-MM-DD.md. Args: "en"/"fr" pour la langue (défaut: fr), "save" pour forcer la sauvegarde.

rtk-ai/rtk · 96 tokens

moai-workflow-project

Integrated project management system covering documentation, language initialization, template optimization, docs generation, and JIT document loading. Absorbed from moai-workflow-templates, moai-docs-generation, and moai-workflow-jit-docs.

modu-ai/moai-adk · 55 tokens

github-operations

GitHub CLI operations for issues, PRs, milestones, and Projects v2. Covers gh commands, REST API patterns, and automation scripts. Use when managing GitHub issues, PRs, milestones, or Projects with gh.

yonatangross/orchestkit · 50 tokens

lane-contract

File-based task contracts under .agents/runs/ with ownspaths, verification tiers L0/L1/L2, and solo merge rules. Use when user says info, справка, lane-stack:lane-contract info, or when authoring or reviewing task YAML, ownspaths, acceptance, or verification commands.

VKirill/claude-lane-stack · 65 tokens

development-team

How the development pod coordinates implementation, QA, and design without skipping gates.

mvschwarz/openrig · 18 tokens